In an unprecedented legal move, California’s legislative leaders have retained former U.S. Attorney General Eric Holder to represent them in anticipated court battles against incoming President Donald Trump.

"The stakes couldn't be higher," California Senate President Pro Tem Kevin de León tells The California Report. "This is potentially the legal fight of a generation."

De León says Trump’s election could "undermine the economic progress of the great state of California." Its gross domestic product grew 4.2 percent in 2015, twice the national rate.

The California Senate and Assembly are splitting the cost of Holder's retention, which will run a minimum of $75,000 over three months.

"Given the urgency, intensity and complexity of the work, these terms are eminently fair and consistent with industry standards," according to a statement from Assembly Speaker Anthony Rendon's office.

Holder is a close friend and confidant to outgoing President Barack Obama, and has been enlisted to lead the Democratic Party’s effort to change redistricting laws across the country. He’s a partner at Covington & Burling, a firm that markets its “Mini State Department” to clients as a way to “navigate their most complex global business problems.”

"I am honored that the Legislature chose Covington to serve as its legal adviser as it considers how to respond to potential changes in federal law that could impact California's residents and policy priorities," Holder said in a statement released by de León and Rendon. "I am confident that our expertise across a wide array of federal legal and regulatory issues will be a great resource to the Legislature."

But Holder's retention raises a tricky question. Why do legislative leaders feel they need legal help outside of presumptive state Attorney General Xavier Becerra?

"I think the more legal firepower we have, the better," de León says. “We’re going to work closely with Xavier Becerra when and if he gets confirmed. We’re going to work closely with Gov. Jerry Brown. But the more legal power, the better."

De León says a motivation to retain Holder is that he will “protect California’s progressive values,” including new minimum wage laws, climate change policies and equal pay for female workers.

Yet, while Holder is a friend to Obama and celebrated by Democratic leaders in Sacramento, he has long been criticized by progressives for a host of policies and decisions -- including failing to prosecute bankers at the center of the Great Recession. While California's leaders have expressed fears about potential actions the Trump administration may take against undocumented immigrants, Holder served an administration that deported a record number of people in the country illegally.

“When you’re at the helm of an institution like the Department of Justice, there’s always going to be controversial decisions, things that didn’t sit well with me,” de León says. “But there’s a lot on the table, including the potential splitting up of mothers from their children with deportations. No one’s perfect, but we’re going to move forward.”

The California Report's Guy Marzorati contributed to this post.